Category: mammals

There was a period before Christmas where we had a lot of snow accumulation on the ground. Some rain over the holidays, followed up by this warm stretch, melted off most of it, and the receding snow can reveal some interesting things that take place under the snow layers, where we can’t see them. One that many homeowners are probably familiar with are these strange half-tunnels carved into grassy lawns. Only an inch or two wide, they can carve intricate networks or simple purposeful trails into the grass and soil which many people find unsightly and can often be difficult to fill in again.

Meadow Vole (Gillian Bowser, NPS Photo)

The culprit, at least here in the east, is the common and widespread Meadow Vole. It’s the only species of vole that occurs in eastern North America, but it’s also found as far west as Alaska. It doesn’t usually come into homes, so like most rodents, it’s rarely seen itself. However, it leaves ample evidence of its presence. The trails in the lawn are a network of pathways that the vole uses to travel between its burrow, where it sleeps and stores food, and the food itself.

In the winter the voles travel under the snow, rather than over it, for three reasons. The first is to avoid predation. It’s much easier for an owl or a fox looking for a meal to track a rodent running across the snow than it is to find something underneath the snow (although these predators are adept at doing that as well!). Also, given the excellent insulative properties of snow, it’s much warmer underneath it all than above it, where the little vole would be exposed to wind and cold. This makes it much easier for the vole to remain active during the winter.

And thirdly, it provides much easier access to its food sources. In the winter, voles will eat seeds and grasses, which are usually found close to the ground, as well as roots and the bark of young saplings. If you have birdfeeders out you might chance to spot one munching on fallen seed when snow cover is low, but more likely the evidence of feeding you’re likely to come across is finding a sapling stripped of bark around its base. Munching by voles can be differentiated from that of rabbits (who will also chew the bark from saplings) in that rabbits won’t usually chew all the way to the ground, and the pattern of gnawing by voles isn’t uniform. I didn’t notice any such saplings around these particular trails. Once the snow melts, you can also often see little piles of grass clippings within the trails, where the vole has snipped the grass off at the base, pulled it down, snipped off some more, etc, until it can reach the seed heads.

This long trail was crossing a narrow stretch of lawn between two naturalized patches (a group of sumacs to a couple of wild apple trees). I’m not sure if the voles are actively foraging for roots or seeds when making these trails, or if they’re directionally challenged (or perhaps just sleepy?), but it seemed like a very curvy trail for just going from one place to another. Perhaps it’s a mechanism to throw off predators listening to rodents running under the snow cover?

Surprisingly, there weren’t very many trails on the lawn, just these couple. In the winter, voles often nest communally in groups of anywhere from two to a number of generations . Female voles breed for the first time when about half grown, at about 25 days. They breed nearly continuously, mating again immediately after giving birth to a litter, and can have three to six litters (depending on latitude and food resources) of four to seven young in a year, which would quickly become quite a large group! Most individuals live less than a year, however. I suppose larger groups would be likely to make a broader network of trails, and a pair would probably just have a handful of well-used trails. A colony of voles can occupy a territory of up to 100 feet in diameter.

Voles aren’t uniformly appreciated by everyone, and particularly in urban settings, the damage to lawns can result in an unsightly mess. There are lots of vole-control solutions to be found by a quick Google search, but my recommendation is just to not have a lawn – plant a garden, it’s more useful to wildlife and prettier anyway! :)

Someone else the recent warm spell brought out is the Red Squirrel that lives at my parents’. They’re rarely seen in the winter, and they tend to be grouped into the “hibernators” category. In fact, there are very few true hibernators, with ground squirrels and bats being the primary groups to do so in North America. Even bears aren’t true hibernators, with only slightly depressed body temperatures and awareness (compare some ground squirrels whose body temperatures may drop to below 0 degrees Celsius!)

Despite what I thought while growing up, Red Squirrels don’t hibernate in the winter either. Instead, they build caches of food near their nest during the fall, which they use, in combination with stored body fat, to get through the winter. They spend most of the winter within their nest, minimizing their amount of activity, and therefore required energy. Because their caches are usually quite close to their nest, they don’t have to stray far, or be out for long, and are not seen often as a result.

So I was delighted to notice that the warm spell had encouraged the resident Red Squirrel to venture out to the feeders to stock up the cache. He (or she) was incredibly quick, dashing from the roof down the tree to the driveway, grabbing a few seeds and perhaps a chunk of bread (my mom throws out the end slices as a treat for the crows), and then turning tail and dashing back up the tree with barely a hesitation. Most of the photos I got of him were of his rear end as he paused to gather some food.

I think he may have been nesting in my parents’ attic, or alternatively in the spruce trees that line the back of the house (the branches of which are a squirrel’s jump away from the edge of the roof). I could tell when he was coming back to the tree to scurry down to the driveway because of the pitter-patter of little feet across the roof above. Red Squirrels usually maintain several nests within their territory (which may be up to 50m in diameter), but tend to favour White Spruce as the nest tree. Spruce seeds make up more than half of the average Red Squirrel’s diet.

I find Red Squirrels to be especially wary. When walking in the woods, they don’t hesitate to dash up a tree and sit on a branch scolding you, even before chipmunks or Gray Squirrels that might also be in the area. In the case of this guy, I had to either be very still at the window (which meant standing with my camera posed for the shot), or stand back from the window. At the slightest movement he would dash halfway back up the tree, where he would pause and investigate the threat (me) for a moment or two. Either that, or take back off straight up the tree if he’d already gathered up some food.